One option may be Beyond Compare. I use it mainly for code, but it can be used with Excel and Word too. You can use the trial, which used to be full blown version, that counts 30 days of actual use and not 30 calendar days.

MS Word has its own document compare function. To a large extent, Excel workbook content can be compared via formulae and, if output as text files (formulae or results), can be compared by Word as for documents generally. No 3rd-party apps are required in such cases.